A chiral 1, 4-oxazin-2-one: asymmetric synthesis versus resolution, structure, conformation and VCD absolute configuration

A Solladié-Cavallo, O Sedy, M Salisova, M Biba…

Index: Solladie-Cavallo; Sedy; Salisova; Biba; Welch; Nafie; Freedman Tetrahedron Asymmetry, 2001 , vol. 12, # 19 p. 2703 - 2707

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Citation Number: 24

Abstract

1, 4-Oxazin-2-one 3 is obtained from 2-pinanone in 4 steps and 78% overall yield. Enantiopure (ee> 99%)(R)-(+)-3 and (S)-(−)-3 were obtained through chiral supercritical fluid chromatography (using a semi preparative Chiralpak AS column) with almost quantitative recovery of material. The structure and the boat-conformation of the lactone ring have been determined by NMR and the absolute configuration determined by VCD.